There are hundreds of different species of bacteria in your intestine. In the past few decades, scientists have discovered that the number and type of bacteria can have a profound impact on your health ( 8 , 9).

Resistant starch feeds the friendly bacteria in your intestine, having a positive effect on the type of bacteria as well as their number (10, 11 ).

When the bacteria digest resistant starches, they form several compounds, including gases and short-chain fatty ac >12 , 13 ).

Summary One of the main reasons why resistant starch improves health, is that it feeds the friendly bacteria in your intestine and increases the production of short-chain fatty acids like butyrate.

When you eat resistant starch, it ends up in your large intestine, where the bacteria digest it and turn it into short-chain fatty acids (14).

The most important of these short-chain fatty acids is butyrate (15).

Butyrate is the preferred fuel of the cells that line your colon ( 16 ).

Therefore, resistant starch both feeds the friendly bacteria and indirectly feeds the cells in your colon by increasing the amount of butyrate.

Resistant starch has several beneficial effects on your colon.

It reduces the pH level, potently reduces inflammation and leads to several beneficial changes that should lower your risk of colorectal cancer, which is the fourth most common cause of cancer death worldw >17 , 18 ).

The short-chain fatty ac >19 , 20).

Due to its therapeutic effects on the colon, resistant starch may a >21 ).

In animal studies, resistant starch has also been shown to increase the absorption of minerals ( 22 , 23 ).

However, the role of butyrate in health and disease needs to be studied properly in people before any strong recommendations can be made.

Summary By increasing the production of butyrate, resistant starch feeds the cells of your colon and leads to various improvements in the function of your digestive system.

Resistant starch has various benefits for metabolic health.

Several studies show that it can improve insulin sensitivity — the responsiveness of your body’s cells to insulin (24).

What’s more, it has a second meal effect, meaning that if you eat resistant starch with breakfast, it will also lower your blood sugar spike at lunch ( 27 ).

The effect on glucose and insulin metabolism is very impressive. Some studies have found a 33–50% improvement in insulin sensitivity after four weeks of consuming 15–30 grams per day ( 28 , 29 ).

The importance of insulin sensitivity cannot be stressed enough.

Having low insulin sensitivity (insulin resistance) is believed to be a major risk factor for several serious diseases, including metabolic syndrome, type 2 diabetes, obesity, heart disease and Alzheimer’s.

By improving insulin sensitivity and lowering blood sugar, resistant starch may help you avoid chronic disease and improve your quality of life.

However, not all studies agree that resistant starch has these beneficial effects. It depends on the individual, the dose and the type of resistant starch.